Overview
Saltwater State Park sits on the eastern shore of Puget Sound in the city of Des Moines, Washington, roughly 15 miles south of downtown Seattle. The park covers approximately 88 acres and includes a sandy-gravel beach, forested upland trails, a campground, and a designated scuba diving area — a relatively rare amenity among Washington State Parks.
The park's name is straightforward: it fronts saltwater, specifically a sheltered cove where McSorley Creek meets Puget Sound. That creek creates a small freshwater-meets-saltwater habitat that attracts shorebirds and is worth a slow walk on its own. The beach itself is a popular swimming and picnic destination for South King County residents throughout summer.
Historically, the site holds significance for both Indigenous peoples and mid-20th-century military history. Archaeological evidence indicates use by the Duwamish people for thousands of years. During World War II, military fortifications were constructed in the area; remnants of concrete bunkers remain visible within the park and add an unexpected layer of history to a beach outing.
Because Saltwater State Park is a Washington State Parks property, a Discover Pass is required for vehicle access (day use). Verify current pass requirements and fees at the Washington State Parks official website before your visit.
Before You Go
Discover Pass
A Washington State Discover Pass is required for day-use vehicle parking at most state parks, including Saltwater. Passes can be purchased online through Washington State Parks, at certain retail outlets, or at self-pay stations on-site. Verify current pricing and availability before your trip.
Camping Reservations
The campground offers standard and utility sites. Reservations are strongly recommended for summer weekends and can typically be made through the Washington State Parks reservation system. Walk-in availability is limited in peak season.
Water Temperature
Puget Sound water temperatures even in summer are cool — generally in the low-to-mid 50s °F (around 11–13 °C). Swimming is popular but plan accordingly; prolonged immersion is uncomfortable without a wetsuit.
Scuba Diving
The park has an established dive site with an artificial reef. Divers should be certified and familiar with cold-water, low-visibility Pacific Northwest diving conditions. Check local dive shops in the Des Moines or Federal Way area for current conditions and equipment rental.
Getting There
By Car
Saltwater State Park is located at approximately 25205 8th Place South, Des Moines, WA. From Seattle, take I-5 south to the Des Moines exit (exit 149), then follow signs west toward the waterfront. The drive is typically 25–35 minutes outside peak traffic hours, though southbound I-5 through Tukwila and SeaTac can be congested during commute times.
By Public Transit
King County Metro operates bus routes in the Des Moines area. The park is not directly served by a stop at the entrance, but bus routes along Pacific Highway South (SR-99) pass reasonably close. Check the King County Metro trip planner for current routes and schedules, as service patterns change periodically. Light rail to the Federal Way Transit Center (Sound Transit Link) with a connecting bus is another option worth checking.
By Bicycle
Cycling to the park is feasible for experienced riders comfortable with mixed traffic. The Des Moines Creek Trail and regional trail connections provide some protected riding, though the final approach involves surface streets. Verify current trail conditions locally.
Things to See & Do
Beach and Swimming
The sheltered cove offers one of the more swimmable beaches in the immediate South Seattle area. A lifeguard is not typically on duty — swim at your own risk and supervise children closely near the water.
Hiking and Nature Walks
Several short trails wind through the forested upland above the beach. The trail network is modest — this is not a destination for all-day hiking — but the forest provides pleasant shade and a contrast to the open beach. McSorley Creek runs through the park and is worth walking alongside for birdwatching.
WWII Bunker Exploration
Concrete military structures from the World War II era are accessible within the park. They provide an interesting historical detour and are popular with curious visitors and photographers. Exercise caution around older concrete structures.
Scuba Diving
The park's artificial reef, created partly from sunken materials, is one of the most accessible shore-diving sites in King County. Divers can expect to encounter rockfish, lingcod, sea stars, and other Puget Sound marine life. Conditions are best at slack tide; consult tide tables before diving.
Picnicking and Camping
Covered and open picnic shelters are available (some may be reservable — verify locally). The campground is forested and reasonably private for a frontcountry setting this close to a major metro area.
Food & Drink
There are no food concessions or restaurants inside Saltwater State Park itself. Pack food and beverages before arriving, and note that alcohol regulations in state parks apply — verify current rules with Washington State Parks.
The city of Des Moines has a small but functional downtown along Marine View Drive, approximately 1–2 miles north of the park. The Des Moines waterfront area has a fishing pier, marina, and a handful of casual restaurants and cafes. Options range from seafood spots to standard American diner fare. Verify hours locally, as small independent restaurants along the waterfront can have seasonal schedules.
Federal Way, a few miles south, and Burien to the north both offer more extensive dining options if you are willing to drive a short distance.
Practical Information
Restrooms and Facilities
Restrooms are available at the park, including near the beach and campground. Facilities are maintained by Washington State Parks; cleanliness and amenity level can vary by season and staffing.
Cell Service
Verizon, AT&T, and T-Mobile generally have usable coverage at the park given its proximity to the Des Moines urban area, but signal can be intermittent in the forested upland sections.
Pets
Dogs are typically permitted on leash in Washington State Parks. Verify current rules at the park entrance or on the official Washington State Parks website, as pet policies on specific beach areas can vary.
Emergency Services
Des Moines is served by South King Fire and Rescue. In any emergency, call 911. The nearest hospital with emergency services is in the broader Des Moines/Federal Way corridor — verify the nearest facility before your visit if you have medical concerns.
Leave No Trace
The park experiences significant use from the Seattle metro population. Pack out all trash, avoid disturbing wildlife in McSorley Creek, and stay on established trails in the upland forest to reduce erosion.
Safety
Saltwater State Park is a generally safe, well-visited public park in a suburban setting. Standard urban-park precautions apply: do not leave valuables visible in parked vehicles, and be aware of your surroundings in the parking area.
Marine safety is the primary concern. Puget Sound has cold water year-round, and no lifeguards are on duty. Rip currents are less common in this sheltered cove than on ocean beaches, but swimmers — especially children — should stay in shallow areas. Scuba divers should be aware that boat traffic exists in the Sound; a dive flag is essential.
The park can draw larger weekend crowds in summer, which occasionally leads to parking overflow and congestion on the access road. Arriving early (before 10 a.m.) on summer weekends is advisable.
